The International Cycling Union (UCI) has been criticised for accepting a cash donation from disgraced Tour de France winner Lance Armstrong.

The UCI has admitted accepting a donation of more than 100,000 US dollars from Armstrong in 2002, but has strongly denied that it was connected to any cover-up of a positive test.

Dr Michael Ashenden, acknowledged as the foremost expert in blood doping and the man whose test caught Armstrong's US Postal team-mate Tyler Hamilton, told BBC Radio Five Live's programme 'Peddlers - Cycling's Dirty Truth': "The UCI should never have accepted money from Armstrong under any circumstances."

He added: "But if they took money after they were aware there were grounds to suspect Armstrong had used EPO it takes on a really sinister complexion."

Ashenden said there was a worrying triangle involving Armstrong, the UCI and a drug-testing laboratory in Lausanne.

"We know Armstrong paid the UCI more than 100,000 US dollars and around that time the UCI gave the Lausanne laboratory free use of a blood analyser worth 60-70,000 US dollars," he said. "That's what I mean by a triangle; the laboratory then meets with Armstrong, all of this takes place at about the time that Floyd Landis and Tyler Hamilton said under oath that Armstrong bragged he had managed to have a result covered up."

A report by the United States Anti-Doping Agency last week labelled Armstrong, who has repeatedly denied doping allegations, a "serial cheat" and a bully who enforced "the most sophisticated, professionalised and successful doping programme that sport has ever seen".

Dick Pound, the former president of the World Anti-Doping Association (WADA), said the UCI could have made greater efforts to have caught drug-taking cyclists.

"They could certainly have done things to ensure they caught more people," he said. "It's generally acknowledged now that for a governing body to promote its sport and to police it puts them in an impossible conflict. The UCI have always been in a difficult position and their behaviour has not always been what you would hope it to be.

Pound added: "There was certainly generalised knowledge that there had been some payments from Armstrong to the UCI. It's hard to think of the UCI as a charity and Lance somebody filled with [charitable] spirit."